This invention relates generally to a clutch disc assembly, especially for motor vehicles comprising:
a hub unit having an axis, said hub unit including a hub and a hub disc fixed on said hub in a position perpendicular to said axis, at least one first circumferentially extending hub disc window with generally radially extending oppositely positioned first and second terminal edges being provided in said hub disc;
a cover disc unit mounted on said hub unit for angular movement about said axis between a neutral angular position and respective terminal angular positions on opposite sides of said neutral angular position, said cover disc unit including, two cover discs, each cover disc being positioned on an opposite side of said hub disc, lining carrier means being provided on one of said cover discs, at least one first circumferentially extending cover disc window with generally radially extending oppositely positioned first and second terminal edges being provided in each of said cover discs, said first cover disc windows of said two cover discs being axially aligned with each other and overlapping said first hub disc window;
at least one first circumferentially extending compression spring with oppositely directed first and second ends being housed within said first hub disc window and said first cover disc windows with said first end adjacent said first terminal edges and said second end adjacent said second terminal edges, said first compression spring functioning as torsion spring means operatively interconnected between said hub unit and said cover disc unit, said torsion spring means resisting angular movement from said neutral angular position toward said terminal angular positions;
friction damping means damping said angular movement of said cover disc unit with respect to said hub unit, said friction damping means including a control disc mounted on said hub unit for angular movement about said axis, a first friction unit operatively interposed between said control disc and said cover disc unit, said first friction unit providing a damping torque having a first torque value, a second friction unit operatively interposed between said control disc and said hub unit, said second friction unit providing a damping torque having a second torque value different from said first torque value, a first abutment member being provided on said control disc, said first abutment member having a spring abutment face and an edge abutment face, said spring abutment face facing said first end of said first compression spring.
A clutch disc assembly of this type is known from British Pat. No. 14 93 002. According to this British patent the damping effect is dependent on the direction of angular movement from said neutral position. The damping effect however remains constant between the neutral angular position and both terminal angular positions.
The present invention is directed toward the task of providing a clutch disc assembly, in which on angular movement from said neutral angular position toward each of said terminal angular positions, the damping effect is changed after a first section of angular movement.